An infectious disease crisis of global proportion is today threatening health care system of many countries. Malaria, caused by protozoan belonging to the genus Plasmodium, is one of the most severe parasitic diseases. According to the World Health Organization (WHO) estimates, nearly four billion people, mostly in the tropical/impoverished countries, are at the risk of malaria. Each year 2-3 million people, mostly youngsters, in more than one hundred countries die from malaria, and its associated complications. Most malaria deaths occur in sub-Saharan Africa, where malaria accounts for one in five of all childhood deaths. Women are especially vulnerable during pregnancy. They are more likely to die from the disease, suffer miscarriages or give birth to premature, low-weight babies (Kevin, B. J. Drugs, 59, p 719, 2000). In India alone, 2.5-2.8 million clinical cases of malaria are reported annually. Civil conflicts, large-scale human migrations, climatic and environmental changes, inadequate and deteriorating health systems, growing insecticide and drug resistance have all combined to bring about the resurgence of malaria. Hence, malaria remains a major burden to human health in tropical and subtropical areas. The estimated global annual cost (in 1995) for malaria is about US $2 billion including that for loss of labor. However, ironically estimated annual expenditure on malaria research, prevention and treatment is approximately US $84 million, underlining the need for more efforts to combat this infectious disease.
The four identified species of the parasite responsible for causing human malaria are Plasmodium falciparum, P. vivax, P. ovale and P. malariae. However, P. falciparum and P. vivax account for more than 95% of malaria cases in the world, and P. falciparum causes most problems as a result of its prevalence, virulence and drug resistance, and nearly all deaths are attributed to this single parasitic species. Malaria infections caused by P. falciparum are prevalent in the major parts of Africa, sub-Saharan Africa and East Asian countries, whereas P. vivax is the causative species primarily of Indian sub-Continent. The disease can be treated in just 48 hours, yet it can cause fatal complications, if the diagnosis and treatment are delayed. Malaria is re-emerging as the biggest infectious killer and is currently the first priority tropical disease of the World Health Organization.
Life cycle of malaria parasite has various stages, and each stage has different degree of susceptibility to available antimalarial agents. The currently available antimalarial agents are conveniently divided into following two categories i.e. blood-schizontocidal antimalarial agents, which exert their biological activity against the erythrocytic asexual (blood) stages of the malaria parasite, and tissue-schizontocidal antimalarial agents, which exert their antimalarial action on the asexual exoerythrocytic (tissue) stages of the human malaria parasite. All of the available antimalarial drugs are losing their power to treat infection and have become inadequate for the treatment of malaria infection. P. falciparum has developed resistance against majority of blood-schizontocides such as chloroquine and mefloquine. On the other hand, available tissue-schizontocide such as primaquine is relatively ineffective against the blood schizonts. Additionally, the toxicity of primaquine requires it to be given in divided doses over 14 days to achieve radical curative effects in humans. These problems could be alleviated by the development of compounds, which, while retaining the tissue-schizontocidal activity of 8-aminoquinolines, have increased blood-schizontocidal activity comparable to that of chloroquine and mefloquine. This would enable single drug treatment for suppression as well as radical cure of the malaria infection. The logical lead compound for this research is primaquine and well supported by following observations: (1) 8-aminoquinolines is the only class of compounds proven to be successful for the treatment of relapsing malaria; (2) the 8-aminoquinolines, such as primaquine are easily synthesized and inexpensive to produce; (3) the 8-aminoquinolines, such as primaquine is the only drug available to exhibit activity against all the stages including that of blood- and tissue-stages of the human malaria life cycle; (4) the 8-aminoquinoline, primaquine has been shown to be effective against drug resistant strains of P. falciparum. 
Despite research efforts of more than 60 years malaria is still one of the major killer of the world. Majority of people suffering from malaria belong to poorer section of society/countries, and are unable to afford expensive treatment. One of the factors for the development of resistance to the majority of drugs is believed to be the poor patient compliance. Therefore, elimination of expensive multi-drug therapies, with single drug will help in reducing the cost of treatment. This reduction in the cost would lead to more patient compliance. This would give better results in the prevention, spread and treatment of malaria.